Pen



FIG. 1 is a perspective view of a pen showing my new design;

FIG. 2 is a top plan view of FIG. 1;

FIG. 3 is a bottom plan view of FIG. 1;

FIG. 4 is a front elevational view of FIG. 1;

FIG. 5 is a side elevational view of FIG. 1, the opposite side being a mirror image; and,

FIG. 6 is a rear elevational view of FIG. 1. 

The ornamental design for a pen, as shown and described. 